A power converter has been conventionally used for driving a motor in a hybrid electric vehicle (HEV) and the like. The power converter includes power semiconductors that cause a large current to flow and thus generates much heat. Therefore, efficient cooling of the power converter is crucial.
Japanese Patent Laid-open No. 2002-270748 discloses a semiconductor module in which conductive parts each having a cooling path therein are connected to a base plate via a resin insulation layer and in which power semiconductor devices are solder-bonded to the conductive parts serving as conductors of a circuit pattern. Another power converter is also disclosed that is configured to connect the cooling path of each conductive part with an insulation pipe, thereby allowing a coolant to flow through the insulation pipe.